Conventionally, there has been a light-emitting diode lighting device that is configured to cause light-emitting diodes connected in series to emit light (refer to Patent literature 1: JP 2006-147933 A). This light-emitting diode lighting device includes a rectifier circuit and a lighting control circuit. The rectifier circuit rectifies an AC voltage into a pulsating voltage, and then supplies the pulsating voltage to a series circuit of the light-emitting diodes. Within a phase range where the pulsating voltage changes from a low value to a high value, the lighting control circuit performs lighting control for the light-emitting diodes so that the number of light-emitting diodes emitting light is increased according to the change in the pulsating voltage. Within a phase range where the pulsating voltage changes from the high value to the low value, the lighting control circuit performs the lighting control for the light-emitting diodes so that the number of light-emitting diodes emitting light is decreased according to a change in the pulsating voltage.
In the light-emitting diode lighting device described above, there is a possibility that a ripple occurs in output light, when the lighting control circuit increases or decreases the number of light-emitting diodes emitting light.